In microfluidic systems, e.g. lab-on-chip (LOC) systems, it is necessary to convey the biochemical reagents and the sample onto/into the chip. In contrast to simple lateral-flow test strips, e.g. for immunological detection methods, several reagents are often needed in the chip system for molecular diagnostic tests. On-chip storage in dried form, for example lyophilized form, which is easy to handle and user-friendly, is not always possible here. Another important difference between most molecular diagnostic tests and lateral-flow test strips is that it is often necessary to handle large amounts of analyte solutions or wash solutions which, because of their large volume of up to several milliliters, are difficult to integrate on the chip.
To meet these requirements, storage vessels external to the chip are used for example, with external syringe pumps and connections to the chip. Alternatively, the reagents are introduced into the storage containers or reaction chambers of the chip manually. While the first variant can easily lead to contamination or air in the syringe pumps, the second variant is associated especially with the problem of operating errors by the users. Moreover, systems in which fluids are added by means of compressed air also known, but the volumes that can be added are reproducible only with difficulty, and compressed air can get into the fluidic system.
For these reasons, systems have been developed in which the reagents are stored directly in an integrated manner on the chip. For this purpose, WO 2006053588 describes a device for use in a microfluidic system, in which a liquid is stored in a blister reservoir. After the blister has been brought into contact with the microfluidic system, a film between the blister reservoir and the microfluidic system is pierced, such that a fluid connection is obtained between the blister reservoir and the microfluidic system. The liquid is then brought into a channel of the microfluidic system by applying manual pressure to the blister reservoir. To ensure that film between the blister reservoir and the microfluidic system is not pierced too early, the system of blister reservoir and microfluidic system comprises a special holding device.
A further device is disclosed in WO 2008076395. In this device, a plurality of blister reservoirs are brought into direct contact with the microfluidic system, and opened by needles, only at the moment when the liquids stored in them are to be used. In addition, by alternate compression of the blister reservoirs, the system allows individual substances to be mixed in the microfluidic system.